54- Roi/al Society. 



similar solution of the chloride by nitrate of silver, and infers the 

 quantity of chloride from that of the fixed horn-silver obtained ; 

 having previously determined, by a separate series of experiments, 

 the exact composition of horn-silver. The conclusion he draws 

 from his researches is, that 100 parts of the chloride of barium 

 correspond to 137'63 parts of the chloride of silver, which latter 

 substance contains 34"016 parts of chlorine, and therefore leaves for 

 the proportion of barium, 65'984- parts. The real equivalent of 

 barium, however, will depend upon that of chlorine, which is itself 

 not yet satisfactorily determined. 



A paper was read, entitled " On the brain as an aggregation of 

 parts ;" by G. Spurzheira, M.D. Communicated by R. Chenevix, 

 Esq., F.R.S. 



The author contends that the human brain should be viewed not 

 as a single organ, but as an aggregate of many different nervous 

 apparatuses, each destined to the performance of a special function. 

 What the peculiar function is which each of the cerebral organs 

 performs, cannot, indeed, be at all inferred from its anatomical 

 structure, but must be gathered from other evidence. In comparing 

 the brains of different animals, this process must be reversed ; and 

 whenever we find organs performing the same function in different 

 animals, we must conclude that they are in reality the same organs, 

 however they may differ in their size, structure, appearance, or si- 

 tuation. The brains of animals belonging to the same class resemble 

 each other in their general type, although the special apparatuses 

 appropriated to each function may vary in their size and number. 



The author next attempts to establish the proposition, that the 

 parts of the healthy human brain are essentially the same, although 

 somewhat modified in their size and quality, in different individuals. 

 In support of this doctrine, he endeavours to show, that the several 

 convolutions on the surface of the cerebrum may be identified in 

 different brains ; and that this identity may be recognized in the 

 two lateral halves of the same brain. On examining the brains of 

 some idiots, he found that certain convolutions, which he believes 

 to be capable of being thus identified, are defective, and others en- 

 tirely wanting. He makes a similar observation on the brain of an 

 ourang-outang which exhibits a closer analogy to the human struc- 

 ture than that of any other mammiferous animal, and in which he 

 could not discern some of the convolutions which exist in the brain 

 of man. The paper was accompanied by drawings of the brain of 

 an idiot, from a preparation in the possession of Mr, Stanley ; and 

 of that of an ourang-outang belonging to Dr. Leach, now deposited 

 in the museum of the Royal College of Surgeons. 



May 21. The President in the chair. — A paper was read, entitled 

 " On the action of grooved surfaces on light ;" by Dr. Brewster, 

 LL.D., F.R.S., &c. 



May 28. — A paper was read, " On the nerves of the face;" by 

 Charles Bell, Esq. 



June 4'. — A paper was read, entitled, " On the geometrical re- 

 presentation of the powers of quantities which involve the square 



roots 



